The most major doubt

[Keeemoman]

Guys there is a very big doubt for me. PLease I need a genius person to solve that.
In November 1997
a question was asked (Question 19), which made me angry with CIE
The same for Question 36
U get the answer right, but it will turn to be wrong according to the mark scheme
Waiting for reply.......

 

[Keeemoman]

Guys there is a very big doubt for me. PLease I need a genius person to solve that.
In November 1997
a question was asked (Question 19), which made me angry with CIE
The same for Question 36
U get the answer right, but it will turn to be wrong according to the mark scheme
Waiting for reply.......

Sorry guys its chemistry paper1 :bad:

 

[skinnyboyfat]

what's da question????
dont have da paper u mentioned...i would suggest u crop and paste that question here.....
or mayb in 1997 people were not so intelligent or there were different theories....lol..

 

[yousef0074]

question 19 is B potassium iodide since there's yellow ppt
question 36 is D C5H12 general formula CnH2n+2

 

[Keeemoman]

Ok
wait

 

[Keeemoman]

Here you go with attachment give me the letters

 

[Keeemoman]

And the marking scheme

 

[CaptainDanger]

36. D

19. B


Marking Scheme is wrong.... Don't worry.... It sometimes is wrong....

 

[xIshtar]

36 is D, and 19 is B,
As yousef already said. If you need further explanation, just ask

 

[Keeemoman]

36 is D, and 19 is B,
As yousef already said. If you need further explanation, just ask

Yes but chek out the marking scheme
I even wrote the same answer but its wrong

 

[Rashu712]

Here you go with attachment give me the letters

I have done Chemistry last year and got an A* but I don't really remember all the things I learned, but
I am 100% sure that the answer for Question 36 is D.

Alkanes have single bonds, and they are chemicals/molecules that contain Carbon and Hydrogen ONLY.
I forgot the general category's name under which Alkanes, Alkenes and Alkynes lie, but the definition
itself states that they are molecules that contain Carbon and Hydrogen ONLY (Only is the keyword).

So the answer D shows Carbon and Hydrogen molecules, with all single bonds.

Structure A I think is a Carboxylic acid (Ethanoic acid I think), if I remember it correctly since there is a -COOH bond, with a double bond to a single
oxygen molecule.

Structure B represents an Alcohol, which has a -OH bond.(I think it's a Propanol)

Structure C is definitely an Alkene. I think it's But-2-ene.

So Structure D is Pentane, an Alkane.



For Question 19, the answer is B.

Only iodide salts produce yellow precipitate. So it's Potassium iodide.

You can check that from the Salt Analysis table.

 

[Rashu712]

Oh, I just read the answers in the Marking Scheme. It doesn't make any sense. I am sure I am not wrong about Question 36...I might be wrong for Question 19 because I don't really remember the salt analysis topic.

The Marking Scheme is probably not the original one, or perhaps it has wrong answers.

 

[Keeemoman]

Man even me I am really sure and for 100% but the question why did they put these answers

 

[Rashu712]

Man even me I am really sure and for 100% but the question why did they put these answers

They are careless. This scares me a lot, if they set these answers to their computer's database and then have the OMR read the answers
the way they prescribe them. That's gotta suck...loss of marks for nothing.

But who'll argue with them?

 

[skinnyboyfat]

mark schemes r sometime's wrong....here's an obvious example.....

 

[skinnyboyfat]

yeah...u r ryt rashu..they have stated on every ms""CIE will not enter into discussion or correspondence in connection with these mark schemes""..they make mistakes....million ov students pay 4 them.... :x :x

 

[CaptainDanger]

There are many other mistakes as well in the marking schemes... When you know you are 110% correct then go with your answer....

 

[Rashu712]

yeah...u r ryt rashu..they have stated on every ms""CIE will not enter into discussion or correspondence in connection with these mark schemes""..they make mistakes....million ov students pay 4 them.... :x :x

Exactly what I meant.

 

[Ali4lyf]

I am weak in bonding so I dont know q(36)
But as far as Question 19 is concerned its C as mentioned in mark scheme that potassium salt reacts(Acidified) with lead(II) NITRATE hence the product will be Potassium Nitrate.
where color is concerned we won't think of it cause its simple equation.They wrote color to confuse the candidate but as far as mark scheme and my thinking is concerned C is correct answer.
and Question 36 is well explained by rashu.As I am weak in that bonding structures.. :|

I hope it helped.

Regards,

 

[skinnyboyfat]

yeah...u r ryt rashu..they have stated on every ms""CIE will not enter into discussion or correspondence in connection with these mark schemes""..they make mistakes....million ov students pay 4 them.... :x :x

Exactly what I meant.

yeah i know that's why in the starting ov my post i wrote...""u r so ryt RASHU""....